Zirconium dioxide is used in the dental sector primarily as a framework material for crowns and bridges, so that high demands are placed on the strength of the material.
WO 99/47065 A1 discloses a method for the production of a tooth replacement that can be fitted to a pre-prepared tooth stump, based on a blank of zirconium dioxide. The blank is a pre-sintered zirconium dioxide disk from which a tooth replacement of corresponding shape is derived, taking into account shrinkage behavior during the through-sintering or end-sintering. Pre-sintering is carried out at a temperature between 850° C. and 1000° C., in particular in the range 850° C. to 900° C., wherein the heat-treatment step for this is carried out for a period of time between 100 minutes and 150 minutes. An inorganic/inorganic composite material and a method for its production are known from WO 2005/070322 A1. To derive the composite material, an open-pore, crystalline oxide ceramic mold part is derived from an oxide ceramic powder of ZrO2 (zirconium dioxide) following shape-providing processing and pre-sintering, with an infiltration substance applied to the said oxide ceramic mold part under vacuum at room temperature and the oxide ceramic sintered in an air atmosphere and at ambient pressure to yield the inorganic-inorganic composite material. These measures are intended to yield an improved esthetic effect.
DE 38 74 006 T2 (U.S. Pat. No. 5,180,696 A) discloses a high-toughness ZrO2 sintered body having a stress-induced transformation ratio of 25% or more, which consists essentially of 40-90 volume % of ZrO2 containing 0.1-3 mol % of Nd2O3 and 0.5-3.5 mol % of Y2O3 as stabilizers.
DE 10 2008 026 980 A (WO 2009/146804 A1) relates to a method for coloring porous ceramics, wherein the ceramic is treated with at least one first solution containing metal ions. In at least one further step the metal ions inserted into the ceramic for coloring are immobilized by means of a second solution by at least one chemical precipitation reaction.